1. Field of the Invention
The present invention relates to a substrate processing system and substrate processing method suitable for a technique which performs patterning a plurality of times on a target film disposed on a substrate, such as a semiconductor wafer.
2. Description of the Related Art
In the process of manufacturing semiconductor devices, a photolithography technique is used for forming a circuit pattern on a target substrate, such as a semiconductor wafer (which may be simply referred to as “wafer” hereinafter). Where a circuit pattern is formed by use of photolithography, a resist film is formed by applying a resist liquid onto a wafer, and is then subjected to light exposure for irradiating the resist film with light in accordance with the circuit pattern, and to a subsequent developing process.
In recent years, semiconductor devices tend to be highly integrated to improve the operation speed and so forth, and photolithography techniques are required to increase the miniaturization level of circuit patterns to be formed on wafers. Conventionally, in light of such demands, an improvement has been made by shortening the wavelength of light used for light exposure. However, this improvement is not sufficient to form ultrafine semiconductor devices of the 45-nm node generation and thereafter.
As a patterning technique for forming ultrafine semiconductor devices of the 45-nm node generation and thereafter, there has been proposed techniques which perform patterning a plurality of times to form a single layer pattern (for example, Jpn. Pat. Appln. KOKAI Publication No. 7-147219). Of them, a technique which performs patterning twice is called double patterning.
In double patterning, light exposure is performed twice by use of different light exposure patterns to form a single layer pattern, and so conventional systems need to repeat photolithography and etching twice. However, in this case, the cost for forming a single layer pattern is doubled and the number of steps is increased, resulting in problems concerning the productivity. In order to solve these problems, there has been proposed a technique which repeats photolithography twice by use of different light exposure patterns and then performs etching.
However, so far, there are no established systems or methods that can efficiently perform double patterning by use of this technique.